1.
Prime meridian
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A prime meridian is a meridian in a geographical coordinate system at which longitude is defined to be 0°. Together, a meridian and its antimeridian form a great circle. This great circle divides the sphere, e. g. the Earth, if one uses directions of East and West from a defined prime meridian, then they can be called Eastern Hemisphere and Western Hemisphere. The most widely used modern meridian is the IERS Reference Meridian and it is derived but deviates slightly from the Greenwich Meridian, which was selected as an international standard in 1884. The notion of longitude was developed by the Greek Eratosthenes in Alexandria, and Hipparchus in Rhodes, but it was Ptolemy who first used a consistent meridian for a world map in his Geographia. The main point is to be comfortably west of the tip of Africa as negative numbers were not yet in use. His prime meridian corresponds to 18°40 west of Winchester today, at that time the chief method of determining longitude was by using the reported times of lunar eclipses in different countries. Ptolemys Geographia was first printed with maps at Bologna in 1477, but there was still a hope that a natural basis for a prime meridian existed. The Tordesillas line was settled at 370 leagues west of Cape Verde. This is shown in Diogo Ribeiros 1529 map, in 1541, Mercator produced his famous 41 cm terrestrial globe and drew his prime meridian precisely through Fuertaventura in the Canaries. His later maps used the Azores, following the magnetic hypothesis, but by the time that Ortelius produced the first modern atlas in 1570, other islands such as Cape Verde were coming into use. In his atlas longitudes were counted from 0° to 360°, not 180°W to 180°E as is usual today and this practice was followed by navigators well into the 18th century. In 1634, Cardinal Richelieu used the westernmost island of the Canaries, Ferro, 19°55 west of Paris, the geographer Delisle decided to round this off to 20°, so that it simply became the meridian of Paris disguised. In the early 18th century the battle was on to improve the determination of longitude at sea, between 1765 and 1811, Nevil Maskelyne published 49 issues of the Nautical Almanac based on the meridian of the Royal Observatory, Greenwich. Maskelynes tables not only made the lunar method practicable, they made the Greenwich meridian the universal reference point. In 1884, at the International Meridian Conference in Washington, D. C.22 countries voted to adopt the Greenwich meridian as the meridian of the world. The French argued for a line, mentioning the Azores and the Bering Strait. In October 1884 the Greenwich Meridian was selected by delegates to the International Meridian Conference held in Washington, united States to be the common zero of longitude and standard of time reckoning throughout the world

2.
North Pole
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The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is defined as the point in the Northern Hemisphere where the Earths axis of rotation meets its surface. The North Pole is the northernmost point on the Earth, lying diametrically opposite the South Pole and it defines geodetic latitude 90° North, as well as the direction of true north. At the North Pole all directions point south, all lines of longitude converge there, along tight latitude circles, counterclockwise is east and clockwise is west. The North Pole is at the center of the Northern Hemisphere, while the South Pole lies on a continental land mass, the North Pole is located in the middle of the Arctic Ocean amid waters that are almost permanently covered with constantly shifting sea ice. This makes it impractical to construct a permanent station at the North Pole, however, the Soviet Union, and later Russia, constructed a number of manned drifting stations on a generally annual basis since 1937, some of which have passed over or very close to the Pole. Since 2002, the Russians have also established a base, Barneo. This operates for a few weeks during early spring, studies in the 2000s predicted that the North Pole may become seasonally ice-free because of Arctic ice shrinkage, with timescales varying from 2016 to the late 21st century or later. The sea depth at the North Pole has been measured at 4,261 m by the Russian Mir submersible in 2007 and at 4,087 m by USS Nautilus in 1958. The nearest land is said to be Kaffeklubben Island, off the northern coast of Greenland about 700 km away. The nearest permanently inhabited place is Alert in the Qikiqtaaluk Region, Nunavut, Canada, around the beginning of the 20th century astronomers noticed a small apparent variation of latitude, as determined for a fixed point on Earth from the observation of stars. Part of this variation could be attributed to a wandering of the Pole across the Earths surface, the wandering has several periodic components and an irregular component. The component with a period of about 435 days is identified with the eight-month wandering predicted by Euler and is now called the Chandler wobble after its discoverer and it is desirable to tie the system of Earth coordinates to fixed landforms. Of course, given plate tectonics and isostasy, there is no system in all geographic features are fixed. Yet the International Earth Rotation and Reference Systems Service and the International Astronomical Union have defined a framework called the International Terrestrial Reference System. As early as the 16th century, many eminent people correctly believed that the North Pole was in a sea and it was therefore hoped that passage could be found through ice floes at favorable times of the year. Several expeditions set out to find the way, generally with whaling ships, one of the earliest expeditions to set out with the explicit intention of reaching the North Pole was that of British naval officer William Edward Parry, who in 1827 reached latitude 82°45′ North. In 1871 the Polaris expedition, a US attempt on the Pole led by Charles Francis Hall, another British Royal Navy attempt on the pole, part of the British Arctic Expedition, by Commander Albert H. Markham reached a then-record 83°2026 North in May 1876 before turning back. An 1879–1881 expedition commanded by US naval officer George W. DeLong ended tragically when their ship, over half the crew, including DeLong, were lost

3.
Arctic Ocean
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The Arctic Ocean is the smallest and shallowest of the worlds five major oceans. Alternatively, the Arctic Ocean can be seen as the northernmost part of the all-encompassing World Ocean, located mostly in the Arctic north polar region in the middle of the Northern Hemisphere, the Arctic Ocean is almost completely surrounded by Eurasia and North America. It is partly covered by sea ice throughout the year and almost completely in winter, the summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center uses satellite data to provide a record of Arctic sea ice cover. The Arctic may become ice free for the first time in human history within a few years or by 2040, for much of European history, the north polar regions remained largely unexplored and their geography conjectural. He was probably describing loose sea ice known today as growlers or bergy bits, his Thule was probably Norway, early cartographers were unsure whether to draw the region around the North Pole as land or water. The makers of navigational charts, more conservative than some of the more fanciful cartographers, tended to leave the region blank and this lack of knowledge of what lay north of the shifting barrier of ice gave rise to a number of conjectures. In England and other European nations, the myth of an Open Polar Sea was persistent, john Barrow, longtime Second Secretary of the British Admiralty, promoted exploration of the region from 1818 to 1845 in search of this. In the United States in the 1850s and 1860s, the explorers Elisha Kane, even quite late in the century, the eminent authority Matthew Fontaine Maury included a description of the Open Polar Sea in his textbook The Physical Geography of the Sea. Nevertheless, as all the explorers who travelled closer and closer to the reported, the polar ice cap is quite thick. Fridtjof Nansen was the first to make a crossing of the Arctic Ocean. The first surface crossing of the ocean was led by Wally Herbert in 1969, in a dog sled expedition from Alaska to Svalbard, with air support. The first nautical transit of the pole was made in 1958 by the submarine USS Nautilus. Since 1937, Soviet and Russian manned drifting ice stations have extensively monitored the Arctic Ocean, scientific settlements were established on the drift ice and carried thousands of kilometres by ice floes. In World War II, the European region of the Arctic Ocean was heavily contested, the Arctic Ocean occupies a roughly circular basin and covers an area of about 14,056,000 km2, almost the size of Antarctica. The coastline is 45,390 km long and it is surrounded by the land masses of Eurasia, North America, Greenland, and by several islands. It is connected to the Pacific Ocean by the Bering Strait and to the Atlantic Ocean through the Greenland Sea, countries bordering the Arctic Ocean are, Russia, Norway, Iceland, Greenland, Canada and the United States. There are several ports and harbours around the Arctic Ocean In Alaska, in Canada, ships may anchor at Churchill in Manitoba, Nanisivik in Nunavut, Tuktoyaktuk or Inuvik in the Northwest territories

4.
Asia
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Asia covers an area of 44,579,000 square kilometres, about 30% of Earths total land area and 8. 7% of the Earths total surface area. The continent, which has long been home to the majority of the population, was the site of many of the first civilizations. Asia is notable for not only its large size and population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, the western boundary with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. The most commonly accepted boundaries place Asia to the east of the Suez Canal, the Ural River, and the Ural Mountains, and south of the Caucasus Mountains, China and India alternated in being the largest economies in the world from 1 to 1800 A. D. The accidental discovery of America by Columbus in search for India demonstrates this deep fascination, the Silk Road became the main East-West trading route in the Asian hitherland while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties, the boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Canal. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia, the border between Asia and Europe was historically defined by European academics. In Sweden, five years after Peters death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia, the Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography. Tatishchev announced that he had proposed the idea to von Strahlenberg, the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century, the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, the border between Asia and the loosely defined region of Oceania is usually placed somewhere in the Malay Archipelago. The terms Southeast Asia and Oceania, devised in the 19th century, have had several different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the possessions of the various empires there. Lewis and Wigen assert, The narrowing of Southeast Asia to its present boundaries was thus a gradual process, Asia is larger and more culturally diverse than Europe. It does not exactly correspond to the borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds there is no or is no substantial physical separation between them

5.
Indian Ocean
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The Indian Ocean is the third largest of the worlds oceanic divisions, covering 70,560,000 km2. It is bounded by Asia on the north, on the west by Africa, on the east by Australia, the Indian Ocean is known as Ratnākara, the mine of gems in ancient Sanskrit literature, and as Hind Mahāsāgar, in Hindi. The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf, the oceans continental shelves are narrow, averaging 200 kilometres in width. An exception is found off Australias western coast, where the width exceeds 1,000 kilometres. The average depth of the ocean is 3,890 m and its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m deep, Sunda Trench has a depth of 7, 258–7,725 m. North of 50° south latitude, 86% of the basin is covered by pelagic sediments. The remaining 14% is layered with terrigenous sediments, glacial outwash dominates the extreme southern latitudes. The major choke points include Bab el Mandeb, Strait of Hormuz, the Lombok Strait, the Strait of Malacca, the Indian Ocean is artificially connected to the Mediterranean Sea through the Suez Canal, which is accessible via the Red Sea. All of the Indian Ocean is in the Eastern Hemisphere and the centre of the Eastern Hemisphere is in this ocean, marginal seas, gulfs, bays and straits of the Indian Ocean include, The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April, from May until October south, in the Arabian Sea the violent Monsoon brings rain to the Indian subcontinent. In the southern hemisphere, the winds are milder. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea, the Indian Ocean is the warmest ocean in the world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, Indian Ocean warming is the largest among the tropical oceans, and about 3 times faster than the warming observed in the Pacific. Research indicates that human induced greenhouse warming, and changes in the frequency, among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Godavari, Krishna, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The oceans currents are controlled by the monsoon. Two large gyres, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, during the winter monsoon, however, currents in the north are reversed. Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, north of 20° south latitude the minimum surface temperature is 22 °C, exceeding 28 °C to the east. Southward of 40° south latitude, temperatures drop quickly, surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia

6.
Southern Ocean
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As such, it is regarded as the fourth-largest of the five principal oceanic divisions, smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This ocean zone is cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters. By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Oceans northern boundary or even existence, considering the part of the Pacific, Atlantic. Others regard the seasonally-fluctuating Antarctic Convergence as the natural boundary, Borders and names for oceans and seas were internationally agreed when the International Hydrographic Bureau, the precusor to the IHO, convened the First International Conference on 24 July 1919. The IHO then published these in its Limits of Oceans and Seas, Australian authorities regard the Southern Ocean as lying immediately south of Australia. Map publishers using the term Southern Ocean on their maps include Hema Maps, Southern Ocean is an obsolete name for the Pacific Ocean or South Pacific, coined by Vasco Núñez de Balboa, the first European to discover it, who approached it from the north. The South Seas is an archaic synonym. A1745 British Act of Parliament established a prize for discovering a Northwest Passage to the Western and Southern Ocean of America, authors using Southern Ocean to name the waters encircling the unknown southern polar regions used varying limits. James Cooks account of his second voyage implies New Caledonia borders it, peacocks 1795 Geographical Dictionary said it lay to the southward of America and Africa, John Payne in 1796 used 40 degrees as the northern limit, the 1827 Edinburgh Gazetteer used 50 degrees. The United Kingdoms South Australia Act 1834 described the waters forming the southern limit of the new colony of South Australia as the Southern Ocean. The Colony of Victorias Legislative Council Act of 1881 delimited part of the division of Bairnsdale as along the New South Wales boundary to the Southern ocean. The limit then followed the west coast of Tasmania southwards to the South East Cape and then went eastwards to Broughton Island, New Zealand, the northern limits of the Southern Ocean were moved southwards in the IHOs 1937 second edition of the Limits of Oceans and Seas. From this edition, much of the northern limit ceased to abut land masses. As is discussed in detail below, prior to the 2002 edition the limits of oceans explicitly excluded the seas lying within each of them. The Great Australian Bight was unnamed in the 1928 edition, and it therefore encompassed former Southern Ocean waters but was technically not inside any of the three adjacent oceans by 1937. To perform direct comparisons of current and former limits of oceans it is necessary to consider, or at least be aware of, the limits of the Atlantic, Pacific and Indian Oceans have therefore been extended South to the Antarctic Continent. The IHO readdressed the question of the Southern Ocean in a survey in 2000, of its 68 member nations,28 responded, and all responding members except Argentina agreed to redefine the ocean, reflecting the importance placed by oceanographers on ocean currents

7.
Antarctica
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It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,000,000 square kilometres, it is the fifth-largest continent, for comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is a desert, with precipitation of only 200 mm along the coast. The temperature in Antarctica has reached −89.2 °C, though the average for the quarter is −63 °C. Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, vegetation, where it occurs, is tundra. The continent, however, remained neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources. In 1895, the first confirmed landing was conducted by a team of Norwegians, Antarctica is a de facto condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then, the treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continents ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations, the name Antarctica is the romanised version of the Greek compound word ἀνταρκτική, feminine of ἀνταρκτικός, meaning opposite to the Arctic, opposite to the north. Aristotle wrote in his book Meteorology about an Antarctic region in c.350 B. C, marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A. D. Before acquiring its present geographical connotations, the term was used for locations that could be defined as opposite to the north. For example, the short-lived French colony established in Brazil in the 16th century was called France Antarctique, the first formal use of the name Antarctica as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. Antarctica has no population and there is no evidence that it was seen by humans until the 19th century. Explorer Matthew Flinders, in particular, has credited with popularising the transfer of the name Terra Australis to Australia. Cook came within about 120 km of the Antarctic coast before retreating in the face of ice in January 1773. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals, according to various organisations, ships captained by three men sighted Antarctica or its ice shelf in 1820, von Bellingshausen, Edward Bransfield, and Nathaniel Palmer

8.
South Pole
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The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where the Earths axis of rotation intersects its surface. It is the southernmost point on the surface of the Earth, situated on the continent of Antarctica, it is the site of the United States Amundsen–Scott South Pole Station, which was established in 1956 and has been permanently staffed since that year. The Geographic South Pole should not be confused with the South Magnetic Pole, the South Pole is at the center of the Southern Hemisphere. For most purposes, the Geographic South Pole is defined as the point of the two points where the Earths axis of rotation intersects its surface. However, the Earths axis of rotation is actually subject to very small wobbles, the geographic coordinates of the South Pole are usually given simply as 90°S, since its longitude is geometrically undefined and irrelevant. When a longitude is desired, it may be given as 0°, at the South Pole, all directions face north. For this reason, directions at the Pole are given relative to grid north, along tight latitude circles, clockwise is east, and counterclockwise is west, opposite to the North Pole. The Geographic South Pole is located on the continent of Antarctica. It sits atop a featureless, barren, windswept and icy plateau at an altitude of 2,835 metres above sea level, and is located about 1,300 km from the nearest open sea at Bay of Whales. The ice is estimated to be about 2,700 metres thick at the Pole, the polar ice sheet is moving at a rate of roughly 10 metres per year in a direction between 37° and 40° west of grid north, down towards the Weddell Sea. Therefore, the position of the station and other artificial features relative to the geographic pole gradually shift over time. The Geographic South Pole is marked by a stake in the ice alongside a small sign, these are repositioned each year in a ceremony on New Years Day to compensate for the movement of the ice. The sign records the respective dates that Roald Amundsen and Robert F. Scott reached the Pole, followed by a quotation from each man. A new marker stake is designed and fabricated each year by staff at the site, the Ceremonial South Pole is an area set aside for photo opportunities at the South Pole Station. It is located around 180 metres from the Geographic South Pole, Amundsens Tent, The tent was erected by the Norwegian expedition led by Roald Amundsen on its arrival on 14 December 1911. It is currently buried beneath the snow and ice in the vicinity of the Pole and it has been designated a Historic Site or Monument, following a proposal by Norway to the Antarctic Treaty Consultative Meeting. In 1820, several expeditions claimed to have been the first to have sighted Antarctica, with the very first being the Russian expedition led by Faddey Bellingshausen and Mikhail Lazarev. The first landing was probably just over a year later when American Captain John Davis, the basic geography of the Antarctic coastline was not understood until the mid-to-late 19th century

9.
Great circle
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A great circle, also known as an orthodrome or Riemannian circle, of a sphere is the intersection of the sphere and a plane that passes through the center point of the sphere. This partial case of a circle of a sphere is opposed to a circle, the intersection of the sphere. Any diameter of any great circle coincides with a diameter of the sphere, and therefore all great circles have the same circumference as each other, a great circle is the largest circle that can be drawn on any given sphere. Every circle in Euclidean 3-space is a circle of exactly one sphere. For most pairs of points on the surface of a sphere, there is a great circle through the two points. The exception is a pair of points, for which there are infinitely many great circles. The minor arc of a circle between two points is the shortest surface-path between them. In this sense, the arc is analogous to “straight lines” in Euclidean geometry. The length of the arc of a great circle is taken as the distance between two points on a surface of a sphere in Riemannian geometry. The great circles are the geodesics of the sphere, in higher dimensions, the great circles on the n-sphere are the intersection of the n-sphere with 2-planes that pass through the origin in the Euclidean space Rn+1. To prove that the arc of a great circle is the shortest path connecting two points on the surface of a sphere, one can apply calculus of variations to it. Consider the class of all paths from a point p to another point q. Introduce spherical coordinates so that p coincides with the north pole. Any curve on the sphere that does not intersect either pole, except possibly at the endpoints, can be parametrized by θ = θ, ϕ = ϕ, a ≤ t ≤ b provided we allow φ to take on arbitrary real values. The infinitesimal arc length in these coordinates is d s = r θ ′2 + ϕ ′2 sin 2 ⁡ θ d t. So the length of a curve γ from p to q is a functional of the curve given by S = r ∫ a b θ ′2 + ϕ ′2 sin 2 ⁡ θ d t. Note that S is at least the length of the meridian from p to q, S ≥ r ∫ a b | θ ′ | d t ≥ r | θ − θ |. Since the starting point and ending point are fixed, S is minimized if and only if φ =0, so the curve must lie on a meridian of the sphere φ = φ0 = constant

10.
Laptev Sea
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The Laptev Sea is a marginal sea of the Arctic Ocean. It is located between the northern coast of Siberia, the Taimyr Peninsula, Severnaya Zemlya and the New Siberian Islands and its northern boundary passes from the Arctic Cape to a point with co-ordinates of 79°N and 139°E, and ends at the Anisiy Cape. The Kara Sea lies to the west, the East Siberian Sea to the east, the sea has a severe climate with temperatures below 0 °C over more than 9 months per year, low water salinity, scarcity of flora, fauna and human population, and low depths. It is frozen most of the time, though clear in August. The sea shores were inhabited for thousands of years by tribes of Yukaghirs and then Evens and Evenks. They were then settled by Yakuts and later by Russians, Russian explorations of the area started in the 17th century. They came from the south via several large rivers which empty into the sea, such as the prominent Lena River, the Khatanga, the Anabar, the Olenyok, the Omoloy, the sea contains several dozen islands, many of which contain well-preserved mammoth remains. Major human activities in the area are mining and navigation on the Northern Sea Route, the largest settlement and port is Tiksi. The International Hydrographic Organization defines the limits of the Laptev Sea as follows, the eastern limit of Kara Sea. A line joining Cape Molotov to the Northern extremity of Kotelni Island, from the Northern extremity of Kotelni Island – through Kotelni Island to Cape Madvejyi. Then through Malyi Island, to Cape Vaguin on Great Liakhov Island, thence to Cape Sviatoy Nos on the main land. Using current geographic names and transcription this definition corresponds to the shown in the map. The seas border starts at Arctic Cape on Komsomolets Island at 81°13′N 95°15′E and connects to Cape Rosa Luxemburg, the next segment crosses Red Army Strait and leads to Cape Vorochilov on October Revolution Island and afterwards through that island to Cape Anuchin at 79°39′37″N 100°21′22″E. Next, the border crosses Shokalsky Strait to Cape Unslicht at 79°25′04″N 102°31′00″E on Bolshevik Island and it goes further through the island to Cape Yevgenov at 78°17′N 104°50′E. From there, the border goes through Vilkitsky Strait to Cape Pronchishchev at 77°32′57″N 105°54′4″E on the Tamyr peninsula, the southern boundary is the shore of the Asian mainland. Prominent features are the Khatanga Gulf and the delta of the Lena River, in the east, the polygon crosses the Dmitry Laptev Strait. It connects Cape Svyatoy Nos at 72. 7°N141. 2°E﻿ /72.7,141. 2﻿ with Cape Vagin at 73°26′0″N 139°50′0″E in the very east of Bolshoy Lyakhovsky Island. Next, the Laptev Sea border crosses Eterikan Strait to Little Lyakhovsky Island at 74. 0833°N140. 5833°E﻿ /74.0833,140. 5833﻿ up to Cape Medvezhiy, finally, there is a segment through Kotelny Island to Cape Anisy, its northernmost headland 76°10′N 138°50′E